The present invention is related to the field of Microelectromechanical Systems (MEMS). More specifically, the present invention is related to integration of film bulk acoustic resonators (FBAR) filters with on-chip inductors.
Radio frequency (RF) front-end passives, such as transceivers and receivers are increasingly needed for wireless communication. These front-end passives include front-end filters. RF front-end filters consist of FBAR have been found to have a number of advantages over other technologies, such as surface acoustic wave (SAW) devices and ceramic filters, particularly at relatively high frequencies. A FBAR filter typically consists of series FBARs as well as shunt FBARs. The bandwidth of a FBAR filter is typically limited by the electromechanical coupling (K2) of piezoelectric materials. For example, the electromechanical coupling (K2) of polycrystalline ZnO films is about 4%, depending on the film's crystal orientation and quality.